Beta-nitro sulfonic compounds and method of making same



i atented June 6, 1956 7 2,510,282 fl-NITRO SULFONIG COMPOUNDS METHOD OF IVIA'KING- SAME; Marvin H. Gold, ChicagoQIlI assi'gnor to The Visking Corpjoration, Chicago, 111;, a corporationof Virginia NoDrawhm... Application Mars 23, 1946,

SeriaLNo. 656,7

This invention, which is' a continuation-inpart ofcopendin'g application Serial-No. 6*1I;929; filedseptember 21", 1945', relates to new chemical compounds and to the method" of making the same. More particularly, "it relates top nitro s'ulfonic acids and salts thereof as well as to a method of preparing the same;

The term 8- (beta) as used-hereindefinesthe arrangement wherein the carbon atom attached to' the nitro' group is adjacent to the carbon atom holdingth'e sulfonic acid group.

The p-nitro sulfonic acids and salts thereof which constitute onephase of this invention can be represented by the following generic formula:

aryl, halogena ammonium or N-substituted' ammonium bi- H a i As is indicated by the above equation, theoretical-1y l mol 0t bisulfite reacts with 1 mol of nitro olefin. In practice, however, a slight excess of bisulfite, is utilized, though, of course, the re ,actants may be used in the theoretical amount required for the reaction or the nitro olefin may be used in excess of the theoretical amount, re-

quiredfor the reaction.

The, reaction is. generally exothermic and. re-

quires external cooling to maintain it at optimum temperature. Nitro olefins. of low molecular weight react with bisulfites. at a lower temperature than those of higher molecular weight.

Though in the preferred operation of the process the. reaction was carried out at a temperature of from 10 C. to 60 0., it, is to be understood, however. that temperatures higher than 60 C. and

lower'than 10 C. can also be used.

/ The nitro. olefin which constitutea ones. of. the

reactants? can. be. represented. by the following general formula:'

hat

whe ein,

R1 represents. hydrogen, alkyl, aryl, halogen,

alkoxy or aryloxyigroup,

R2, represents; hydrogen, alkyl. aryl, halogen.

allzoxy or aryloxyr lloup, and: Ra represents hydrogen; alkyh. aryl; halogen,

alkoXyor-aryloxygroup.

Asillustrative specific nitro olefins which can be used-in the process are the following: 2-nitro-1-butene Z-phenyI r-nitroethyIene l-nitro'propene 2*-nitropropene- Nitrcethylene- I-phenyl-r-nitroethylene 1 -phenyl- 1 -nitroprop ene 1 naphthyl-l--nitroethylene* l naphthyl-r-nitropropene 2-naphthy1-I-nitropropene l'echlbro r-nitroethylene 1-ch1'oro-1-nitropropene I-methoxy-l-nitroethylene 1 methoxy-z-nitroethylene Z methoxy-2 phenyl -l-nitroethylene 2-phenoxy-lnitroethylene In place of, the nitro olefins, nitro cyclsj. com;- p s su h. asl-ni rncyclohex e nd, ..-msihy l-n tr cyc 'oh xe e. can sed es e I? the reactants.

The bisulfite which is, utilized in the process can be any metal, ammonium, or N-substituted ammonium bisulfite which is water-soluble. Alkali metal bisulfites (such as sodium bisulfite and potassium bisulfite), calcium bisulfite; mag ne iumbi ulfii zin bis flt etc.- re, i lus ra iv metal" bi'sul'fi'tes which canbe used in the process. Bisulfites of t e foll wi g u s bstitutesli m+ m. ns. are; llustrative. examples, o spec N- 'iu d' ammoni m bisulfit s' wh h. a b used inthe precede: Any alka d Methyl" ammonium, cinema/ mmqniuini. me y1' ammon um Methyl dibenzyl' ammonium, Dimethyl benzyl ammonium, Diethyl phenyl ammonium, Cetyl' dimethyl" ammonium, jQuinolinium,

Pyridinium,

Morpholine N methy l morpholine', Ethyl d-i'ethanolammonium,

Triethanol ammonium, I Piperidinium, N-metnyl piperidinium, etc.

In general, in order to obtain the desired nitrosuli'onate the pH of the aqueous solution of the selected bisulfite must usually be at least 5.4. When the selected aqueous bisulfite solution is of a pH lower than 5.3, the pH tends to drop to lower values during the course of the reaction and may drop to as low as 1.5 or lower. 1

Under such conditions, practically none 01' the desired nitrosulionate can be isolated and only one-half of the theoretical amount of nitro olefin is used up. The product or products which result under such conditions of low pH value are extremely water-soluble, hygroscopic and difficuit to purify.

When the selected aqueous solution of the selected bisuliite is of a pH of from 5.3 to below 5.4 the pH of the reaction mixture remains somewhat constant, and a mixture of the desired nitrosulionate and the water-soluble product obtained under low pH condition is obtained.

When the aqueous solution of the selected bisulfite is oi a pii oi at least 5.4, such as between 6 and l and preferably 6.2 to 6.8, only the desired nitrosuironate is obtained. With bisulfate solutions oi such pHs (5.4 to 7), the alkalinity of the reaction mixture increases so that the pH of the reaction mixture rises as the reaction proceeds.

When the pI-I of the bisulfite solution is such that the pH of the reaction mixture rises above about 7.5, the resulting mtrosuiionates tend to enolize and then form salts oi the acid hydrogen of the enolic nitro groups. Thus, the reaction mixture at pHs above 7.5 tends to consist of a mixture of the normal nitrosulfonate salt and the enol nitrosulionate double salt. This mixture can all be reconverted back to the normal salt by lowering the pH to, for example, between 6 and 7. The lowering of the pH can be obtained by acidifying the reaction mixture, such as preferably with sulfur dioxide.

When an aqueous solution of a sulfite, such as sodium or potassium sulfite which has a pH within the range or" about 9.5 to 10.0, is reacted with a nitro olefin, only the enol sulionate double salt is obtained. The chemical structure of such a salt can be represented by the following general formula:

M represents the metallic ion, ammonium or substituted ammonium,

R represents either a hydrogen, alkyl, aryl,

alkoxy, aryloxyl, or halogen group, and

R1 represents either a hydrogen, alkyl, aryl alkoxy, aryloxyl, or halogen group.

The precise double salt depends on the reactants employed. Any of the olefins and any of the sulfites of the metal, ammonium or substituted ammonium ion hereinbefore mentioned can be used.

Herein, wherever pH values are referred to, it is to be understood that they were determined electromatically with a glass electrode. In general, when the pH of the bisulfite solution is to be increased, it is accomplished by means of bases corresponding to the cation of the bisulfite being used, and, when it is to be decreased, it is 4 eiiected by acids or anhydrides corresponding to the anion of the bisulfite used.

The invention can be practiced either by adjusting the pH of the bisulfite solution prior to the reaction or by maintaining the pH of the reaction mixture. In the latter process, the nitro olefin can be continuously added to an aqueous solution of the selected bisulfite held at the desired pH, such as 6 to 7, by adding sulfur dioxide and the required base (metal oxide, metal hydroxide, ammonia, or N substituted ammonia) at such a ratio as to maintain the pH between 6 and 7 at a rate equivalent to the added nitro olefin. By continuously removing a portion of the reaction mixture to separate the crystalline product therefrom and returning the resultant filtrate in a continuous manner to the reaction mixture, the process can be made continuous.

The previously described process or" preparing nitrosuli'onate salts produces a metal, ammonium, or N-substltuted ammonium salt of 5- nitro sulionic acid. Such a salt can, in accordance with another phase of this invention, be converted to the corresponding free nitro sulionic acid or a salt containing any desired cation. OI course, a nitrosullonate salt containing a desired cation can also be obtained directly by the use of a bisulilte salt or such cation.

The free nitro sulionic acid is prepared, in general, from the bisuiiite addition product by ion exchange using any of the well-Known ion exchange procedures and materials, such as, for example, a cation exchange resin. Thus, by passing a salt of the nitro sulionic acid through a column of an acid rorm oi cation exchange resin, an aqueous solution of the free nitro sulionic acid is obtained. The solution of the free nitro sulionic acid can be concentrated or diluted as desired by the appropriate removal or addition of water. If desired, the free sulfonic acid can be removed from solution in any appropriate manner.

In that form of the invention wherein a salt having a cation other than that obtained by the hereinbeiore described bisulfite addition process is desired, such salt can be obtained by appropriate reaction of the free nitro sulionic acid and a compound containing the desired cation. In one embodiment of this form of the invention, the aqueous solution of the free nitro sulfonic acid obtained from a column of a cation exchange resin with or without dilution or concentration as desired is treated with an equivalent quantity of an oxide, hydroxide, or carbonate of any desired cation or substituted ammonia. The salts are obtained by evaporation of the water and are purified by recrystallization from appropriate solvents.

Alternatively, a solution of a bisulfite addition product can be passed over a cation exchange resin which has been converted to the desired cation form. The resulting aqueous effluent contains the new cation salt of the nitro sulfonic acids.

The fi-nitro sulfonic acids or their salts can also, in accordance with another phase of this invention, be converted to the corresponding p-amino sulfonic acids. According to this phase of the invention, the hereinbefore mentioned ,B-nitro sulfonic acids or salts thereof are reduced to the corresponding amino sulfonic acid.

The precise fi-amino sulfonic acid obtained depends on the ,B-nitro sulfonic acid or salt thereof reduced. In general, the B-amino sulfonic represents hydrogen," alkylfaryl; alkoxyor aryloxy group; and.' 7

R3 represents "hydrogen; alkyly aryl; alkoxyior" aryloxy group. Preferably, the. .reduction carried." out f by;

either. an..,iron. reduction..inl,.aqueous solutidn or y tion t ,1. resulting-@185 by hydrogenization usingza catalytie'agent, such as..nickel, although other known reducingiproe cedures can .be..used.

The .manner and fldetailsk for. practicing the inventionwill become. more apparent from the. gozzmethyl gisobutyllketonez and .cao1ing,ima;refr

specific examples hereinafter. set forth," it being understood thatithe invention is. not restricted to..such specific .examples. -which are set. forthas, illustrative --embodiments only; In" the excempesitiene Bramble"? To a well-stirredsolution of saiibamsbr a" 43% aqueous ammoniu'iiibis'iilfite solution of a pHiof e and-warmed to 30 wasedded md parts of: 1-nitroprepene over 'a periodof tliirty minutes while the reacti'on temperature was"kept betweem 35 i-40 by. external cooling Aftei the additioflwast-completed; stirring was' continue'd; whi thes' temperature was kept between =35 -40 fo solution twas: concentrated 'under reduc'ed pres sure to 'a thick viscous oil; 'This was-taken inohot' i ethanoly leaving behind a. small aniountfi of inorganic: bisulfite: Upon-' tlie' addition of erator to a temperatIIrebf- S a 'total-of 350 par (in three crops), corresponding to 83% yield of ammonium-l-nitropropane-2-sulfonate, was obtained: The purified produot,after several reamp1e he p op rtions r p r sby'w i h n ci'ystallizations from ethanolmethyfisobutyl' the temperatures are the uncorrected centigrade thermometer readings.

PREPARATION OF SALTS OF fi-NITRYOSUL- FONICACIDS Ertample i Tara, --:.well:stirred solution'iof -538 :parts -'0f"'3, 43% aqueous: ammonium bisulfite solution a of: apI-li'of sand initiallybroughto. was addeda 226? parts of :2-nitro-l-.butene-:over aperiod -oft, fifteen.minutes.- By external zcooling, .thevre action temperature-was kept between --40-.-* The; crystalline productseparatede'asethe reac=- tionaproceeded; When addition -was ecomplete; stir-ringz'wascontinued-while: the temperaturewvas kept vbetween 35:-40' for ,thirty;.minutes longerl: Then thezreaction mixturewas 0001861410 110-. and the product separated by filtration. The filtrate: was concentrated and additional quantities of the product were recovered by crystallizationtherefrom to give .a vfinalnyieldnof. 88%. .of am! monium-z-nitrobutane- 1 sulfonate.- A sample purified for analysis. by..- crystallization. from methanol melted withdecompositionat 203 206.

43%. aqueous ammoniumbisulfite solution of aw pI-I of 6 and warmed to wasaddedasolutioxi.

40:31 11:19 crystalline product was separated by. filt keton e mixture'sfmelt'ed at 141 -143? Th s productis of 'a soft waxy'crystallinenature and" appears to form solid'gels" witlr'solvnts 's'uclff; ashenzene andvarious ketonesz" Eaiample -el To eiweuestmedrsoiutionof aoo' partsseesaw aqueous: ammoniurn 'bi'sulfite 'soIution havingpH of 6 was added 72.6 parts' of 2 nitropropenes ;over a period of 'fifteenaminutes. The reaction temperature waskeptvbetween. 30-40 by externalfizaooling.v Stirring was continued for an ad di ti'onal I'thiity' "minutes I at room temperature: Thenthe reaction mixture'was cooiedto lor'a'nd' 1 tio'ri. some additional materiahwas obtaine'd' byf"crystalliz'ation at io rrorn the filtrate "after inorganic "salts precipitated w-ith' rnetharihl were" removed and the'filtra'te concentrated underre duced pressure. A total yield of 135 parts (87% yield) 1 of ammonium-2 nitropropanel-sulfonate was recovered in'this manner. The product purified for analysis by recrystallization from methanol melted with decompositioh"*at 190- Example 5 To a, WeII-Stirred sOlutEoh of 125 parts of a. 43 aqueous ammoniumbisulfite solution of a pH Qi-B andheld'at 15 20 was added 38- parts of of 15 parts -phenyl-l-n o partsttfi "pure nitroetliylene iov ua -peri'od (if'tl'iiity mindioxan over a period of about five minutes while keeping the-reaction temperaturearat 40f by ex ternal cooling. After stirringuthemeaction mass while the temperature ;was maintainedizat 40;

utes. --Stirrin-gwas then ontin ued at room temperature for" an i-additional -'thirty minutes. At the'en'dfof this period the reaction mixture was cooledto "5" and the"-'crystallin'e product sepby means of an ice-bath, thereby causing crystal lization of'the reaction-product. The crystallized.

product was removedby-filtration;- The-addi tional reaction product'was isolated in 5a similar manner after concentratingeethe filtrate "analysis-byrecrystallization-from eth'anol'melted reduced pressure. The desired product was then separated from inorganic material? by takinggup in qhot: ethanol. Upon the *aclditiomv of abenzene and allowing .the material to crystallize slowly, 20 parts (80% yield) 1-phenylethane-'1-sulfonate"'was obtained, melting with decompositiomat"HOPE-174. This materialawas vfound. to have: two melting, points. Upon -.rapid;1crystallization. from concentrated.

- of.- 2o;3'0" T2556: kg. or z'mrnmgnmtefiem eth'anolic solutions, a low melting form 'could'" added. During the course of'the readtionfsulfur;

with decomposition at 191.5-192.

Example "6 The pH of a quantity of airaqueous saturated? of ammoniumuz -"nitro solution of ammoniumr bisul-fitecontainingan excess of ammonium bisuliitJ-regflred for reaction' was adjusted-to 6.5.; While such solution was well stirred and heldat a temperature;

dioxide and ammonia were bubbled into the solution so as to maintain a constant pH of 6.5. When the addition was completed, the reaction mixture was cooled and the crystalline product filtered. The dried product which analyzed for about 1% inorganic sulfate amounted to 5000 g. or 97.8% yield.

Example 7 A solution of 105 g. C. P. sodium metabisulfite (0.5 mol) in 300 cc. water gave a pH of 3.9 when measured by means of a glass electrode. Upon the addition of 20 cc. of 50% sodium hydroxide the pH was raised to 6.2. Then 100 g. of 2-nitrol-butene was added with eflicient stirring while keeping the temperature below 40 C. When the addition was completed the material was cooled and filtered. The filtrate was concentrated and cooled, causing it to deposit a second crop of crystals. The total yield was 150 g. (86%) of sodium 2-nitrobutane1-sulfonate. The product melted at 224 with decomposition.

Example 8 A solution of 122 g. C. P. potassium metabisulfite (0.5 mol) in 300 cc. water gave a pH of 4.85 when measured with a glass electrode. Upon the addition of cc. of 50% potassium hydroxide the pH was raised to 5.5. Then 100 g. of 2-nitrol-butene was added with efficient stirring while keeping the temperature below 40. When the addition wa completed, the crystalline product was isolated, as in Example 7, to give 145 g. (77%) yield of potassium 2-nitro-butane-l-sulfonate. It melted at 234 C.

Example 9 A solution of 130 g. (1.03 mol) sodium sulflte in 600 cc. water gave a pH reading of 9.79 with a glass electrode. The solution was stirred rapidly and 100 g. of 2-nitro-l-butene was added dropwise while holding the temperature at about 40 C. The aqueous solution which resulted was then concentrated under reduced pressure to give a mass of crystals M. P. 190 C.

8 PREPARATION OF B-NITRO SULFONIC ACID AND SALTS THEREOF Example 10 A glass column filled with Zeo Karb cation exchange resin was treated with a 4% aqueous solution of hydrochloric acid to convert the resin to the acid form. Then excess acid was removed by washing the column with distilled water until no more chloride ion could be detected in the effluent. Next a solution of g. of ammonium- 2-nitrobutane-1-sulfonate in 1250 cc. distilled water was passed through the column. The exchange was completed by washing With distilled water until the eflluent no longer gave a test for acidity. The combined eflluent contained the free 2-nitro-butane-l-sulfonic acid. It was measured and an aliquot portion titrated for acidity. The selected amine, oxide, hydroxide or carbonate in equivalent quantity was reacted with the solution and, upon evaporation of the mixture, the corresponding salt of the nitro sulfonic acid was obtained. Several illustrative salts and their analyses obtained in this procedure are listed in the Table I hereinafter set forth.

PREPARATION OF SALTS OF fl-NITRO SULFONIC ACID BY ION EXCHANGE Example 11 The column of a Zeo Karb ion exchange resin was saturated with a dilute aqueous solution containing 3%-5% of sodium chloride. Then after washing the column thoroughly with distilled water, a 4% solution of ammonium-Z-nitrobutane-l-sulfonate was passed through. The efiluent and washings were concentrated on the steam bath to give sodium-Z-nitrobutane-l-sulfonate, which is identical with the product obtained by the procedure of Example 10 when sodium carbonate or hydroxide was reacted with the free acid.

TABLE I.--SALTS OF fi-NITRO SULFONIO ACIDS Per Cent Cation Per Cent Nitrogen Per Cent Sulfur Example Formula M. P., O.

Found Theory Found Theory Found Theory l CQH5OI'I(NO2)OH2SO3NH4 203206 dec 13.51 13.99 16. 03 15.91 CBH5CH(SO3NH4) CHzNO' l30131 11. 20 11. 29 12. 90 12. 90

170-171 dec OH OH(SO3NH4) CHzNOa l4l143 14. 57 15.05 17.43 17. 22 CH3CH(NOZ)CH2SO3NH4 190191 den 14. 46 15. 05 17. 04 17. 22 NO2OH20H2SO3NH4 l9l.5192.5 dec.-- 16. 20 16. 23 19.11 18. 63 CgH5CH NOz (DH- S O3Na 224 C2H OH(NO )CHzSOaK 234 C H OH(NO2) CHzSO3N3, 225 dec 11.0 11. 2 15.15 15.6 CzH5CH(N02)GH2SO K 232 dec- 17. 6 17.7 14.1 14. 5 (C2H CH(NOg)OHgSO3)2Ba 260 (1%.. 27. 5 27.4 10.3 10.0 (0 H5CH(NO2)CHQS03)2Oa 300 9. 94 9. 9 7. 22 6. 95 15. 15. 85 (CzH5CH(N0z)CH2SO3)2CO 2l02ll dec 13.33 13. 9 6. 26 6. 62 GgH CH(NOz) CHzSOaIL-.- l9ll92 der 3. 54 3. 62 8. 25 8.27 C2H5CH(NO2)CH2SO3.BIL1O' 187l90 (lee Y 7. 6-1 7. 27 5. 56 5. 58 (O H5OH(N 0;) CHIS 03)2Pb* 145-148 dec 37.1 36. 2 4. 38 4. 9 (C1H OH(NO;)CH SO )zZnT l68l72 dec 14.6 15.1 13.9 14. 9

*The lead salt does not give a sharp analysis as it was contaminated by a polymeric lead salt, which could not be removed completely after many recrystallizations.

TThe zinc salt was difficult to purify due to its extreme tendency toward coordination with most crystallization solvents.

Analysis for the enol double salt.-

C4I-I7O5NSNa2 The properties of the products of Examples l-11 inclusive are set forth in the following table:

PREPARATION OF ,B-AMINO SULFONIC ACIDS Example 12 In a reaction vessel fitted with efiioient stirrer sodium-Z-nitrobutane-1-sulfonate was recovered. and reflux condenser were placed 12 parts of iron filings-amid: "55111133135 oftwater. zz'lhen with rapid agitatiorwrasaddeduilfi part #concentratedhydrochl'oricracid. Thezmixture' wasiheateditoarefiux and'ith'en 8' :parts: oframmonium l-nitropro-pane- 2=suli onateiri :15 pairts iofa waterwere. addedidropwise. f 'lhehreaction was'stirredrand refluxed 'for four hours. 'l hen ftheoprecipitat'ediiron.oxides were removed by filtration of the hotfsolution. The filtratewas rthem made 'slightly. 1 alkalineawith ammonium hydroxide and a littlehydTOgemperoxide added to oxidize ferrous ions to ferric. After stirring withatlittlecharcoal and filtering, the filtrate was evaporated to a small volume. Addition of ethyl alcohol caused the slow crystallization of 1-aminopropane-2-sulfonic acid.

Recrystallization from aqueous alcoholgave -'a product melting with decomposition at283:286.

...Example .13

-In a suitable reaction-vessel were'pl'aced-92-parts of iron filings and 150 parts of water. Theainixturewwas'vigorouslystirredand -1.-5-parts*of concentrated fhydro'clrlori'de -acid 'were added. .zAfter five-:minutes 137.2 s arts of 'ammonium z nitroethanees-bsulfonate and a-50yparts' moreof water werezadded. zThe reaction:emixture was slowly heated to reflux over a period of fifteen minutes. lihen a'esolutiombf st50ipartseconcentrated :hydrochlorimaoid in 50 parts=of water was added dropwise with continued reflux over arpe'riod .ofthirtyfive minutes. Aiter.refluxingandstirring.for an additional-hum the. reactionmixture .was clarified with .charcoal and evaporated to .a small volume. -.Upbn .addition ..of .ethylalcohol; the desired f .2:-aminoethane-1-su1fonic acid crystallized fr0m..so111.tion. iJSeyer'al recry'sta1lizati0ns from aqueous ethyl alcohol gave a product decomposing at 310. "A mixed melting point with an authentic sample' of-'-'taurine gave no lowering in melting point.

Example 14 ""In"a"suitable' reaction vessel wereiilaced 42 parts bfiron "fi1in'gs-and '50 parts-of water. Vigorous agitation was employed and 1 part-"of concentrated hydrochloricacidwas added. After five'minutesa solution-6f62--partsbf ammonium- Z-nitropropane-l-sulfonate in 50 parts of water was added. "The reaction mixture was then gradua1ly"heated to reflux. *At'the point oflreflux as'bliz'tion of 23 "parts"hydroch1oric acid "'in50 parts of water was* added dropwise over aperiod of thirty minutes, after which r'efiux-was continued tdthaend of: an :hour. T-h6 1'lOt' SO1l1fiUn wasfiiterediandw th'e =:precipitated :iron oxide was washed with "water. "The icombined wasliin'gs were made "baSic' With'ammonia' andZtreaterikwith az-little rhydrogen peroxide. "Thenafter clarification with *charco til; :the' solix-tibn was concentrated and a .li'ttlerethyl alcohol a'dd'ed. l'heresulting 2-aminopropane-l-sulfonic acid, after severalrecrystallizationsyimelted "at 1:3 l&-*'-320awithrdec0mposition.

lzample 15 iIn' -a, suitablereaction vessel were placed 35 parts ofiron" filings and parts of water. Vigorousagitation-was employed and 1' part of concentratedhydrochloric acid was added. After five'minutes'ofstirring, '50 partsof ammoniumz-nitrobutane-l-sulfonate were added, followed by""'75-ipa rts" more ofwater. The mixture was gradually h'eated to' reflux and then 16 parts concentrated*liydrochloric "acid in 20 parts "of water-"were added dropwise"over a period of twenty" minutes. After continued stirring and refluxing for -'one"hour," the hot mixture was filtered. The precipitated iron oxides were washedwitlrwarm water. The combined filtrate and wa's'hings ere'made basic with ammonia and treated with a little "hydrogen peroxide. Then'after clarifying the solution with charcoal, itwas concentrated"to asmall volume and allowed'""tocry'stallize. The resulting Z-aminobii tane l siilfonic"acid, after several "recrystalliz'ations fromwatenmeltd with decomposition at BOQ -QUGfi A mixture of" 20.jparts of ammonium-'2-.nitro- Exempted? In assu'itableireaction vessel wereplaced-EO partsof-iron filings. and .100 oartsofwater. .The mixture was.stirredryi orouslyand 1 partof hy-. drochloric .acidwaeadded. .I'hen .heat was .applied and there-action brought to the reflux.tem-- perature. .At this poinhrasolution of..15. .parts.of

ammonium-z-riitrc l -..ohenyletbane 1 sulfo-.

nate in 50 parts-of .water .was .droppedin over a period of fifteenminutes. .Then the -..reaction wasstirred underirefiux .for three. hours. .At the end of this. period the hot tmixture was filtered.-

The filtrate wasmade basic .withcammonia and then oxidized with ..a little hydrogen -peroxide.

Theneafter :clar'iiying. with. charcoal, thersolution.

was concentrated and a littlem'ethanol added. The-2 -amino-lephenylethane .1- -.-.sulfonic' acid crystallizedein whiteaplatelets. Recrystallization from aqueous .methanoLgave arproduct melting. at 379 with decomposition.

The properties of the products rof Examples 12-17 inclusive Ware set ;forth in l the 1 following table:

It is to be understood that the foregoing data of Tables I and II were obtained from single preparations of each of the compounds, and, while such data will be useful in identifying these compounds, it is to be understood that the invention is not limited to products having the exact constants listed.

The Zeo Karb cation resin utilized in Examples and 11 (product of Permutit Company) consists essentially of a sulfonated coal. Obviously, the invention is not restricted to such specific ion exchange resin and that other of the known appropriate ion exchange resins or salts can beused. The embodiment of the invention set forth in Example 11 is particularly suitable for monovalent cations, such as sodium, potassium, lithium, thallium, substituted ammonias, etc.

The ammonium salts of the nitro sulfonic acids are neutral salts, and, as shown in Examples 12-17 inclusive, such salts can be reduced to the corresponding amino compounds. The amino group is a basic group and, during the process of producing the same, produces an internal salt with the sulfonic radical which liberates free ammonia. The free ammonia is either vaporized out of the reaction mixture or neutralized by the addition of an acid, such as hydrochloric. When the cation of the salt of the nitro sulfonic acid undergoing reduction is a metal, an acid is added, as the reaction proceeds, to neutralize the metal hydroxide produced and form a neutral salt thereof. For example, if a calcium salt of the nitro sulfonic acid were reduced, an acid would be added, as the reaction proceeds, to neutralize the calcium hydroxide and. form a neutral calcium salt.

In the method of reducing the salts of the nitro sulfonic acids, wherein the reduction is obtained through the use of iron, ferrous ions are produced. Ferric hydroxide is less soluble than ferrous hydroxide. Consequently, after the reduction operation all the iron is converted to the ferric state in order that it may be precipitated more completely and removed from the solution.

Any appropriate oxidizing agent to convert the ferrous ions to ferric ions can be used. Air may constitute such an oxidizing agent and when used it can be bubbled through the reaction medium. However, hydrogen peroxide is the preferred oxidizing agent since its action is faster and does not introduce any additional ions which mi ht complicate the isolation of a pure product.

The use of charcoal in Examples 12-1? is not critical. It is used for the purpose of clarifyin the reaction mixture when a pure white crystallized product is desired.

The instant invention provides nitro sulfonic acids and salts thereof which have not been previously known or described, and also new and effective processes for the production of such acids and salts.

The nitro sulfonic acids and salts thereof are useful as intermediates for chemical synthesis, and also, in certain cases, may find uses as weting, detergent, or emulsifying agents.

The simplest'p-amino sulfonic acid is known as taurine, which has been obtained by hydrolysis of taurocholic acid, and which has been found useful in the preparation of wetting, detergent and emulsifying agents. However, the major deterrent to its wider use has been its relatively high price.

The reduction of the new nitro sulfonic acids and salts thereof to the corresponding ,B-amino sulfonic acids provides a new procedure for the.

production of taurine and taurine-homologues' by a relatively simple and cheap procedure.

Since it is obvious that various changes and modifications may be made in the above description without departing from the nature or spirit thereof, this invention is not restricted thereto except as set forth in the appended claims.

I claim: 1. A chemical compound having the following structural formula:

R2 (E-SOaM R1 R3 wherein 2. Ammonium-2-nitroethane-1-sulfonate.

3. Ammonium-2-nitropropane-l-sulfonate.

4. Ammonium-2-nitrobutane-1-su1fonate.

5. A method of preparing p-nitro sulfonic compounds which comprises reacting a nitro olefin having the following structural formula:

3 wherein R1 is a member of the group which consists of hydrogen, alkyl, aryl, halogen and alkoxy radicals,

R2 is a member of the group which consists of hydrogen, alkyl, aryl, alkoxy, and aryloxy radicals,

R3 is a member of the group which consists of hydrogen, alkyl and aryl radicals and alkylene radicals in which case R1 and R3 and the carbon atoms linked by the double bond together form a cyclo olefinic ring,

with an aqueous solution of a compound selected from the group which consists of water soluble sulfites and bisulfltes in which the cation is selected from the group consisting of metals, ammonium, and N-substituted ammonium ions, said solution having a pH of at least 5.4 and removing the product from the reaction mixture at a pH of from 6 to 7.

6. A method of preparing B-nitro sulfonic compounds which comprises reacting a nitro olefin having the following structural formula:

r m-ta k wherein R1 is a member of the group which consists of hydrogen, alkyl, aryl, halogen and alkoxy radicals,

R2 is a member of the group which consists of hydrogen, alkyl, aryl, alkoxy. and aryloxv radicals,

some 13 R3 is a member of the group which consists-Lot r i'idm rels ndem-s di al mn lktl n .J;adica1s.,in which case fil agi; an, d,i',he. .,car-

bon atoms linked by the double bond together form a cycle olefinic ring,

With-an aqueous solution pt: a ,compound eglfiated from the group which consists of water uble suliitesrandbisulfites in which? the cation is se- R1 is a memberz-hfr thesgmuprwhichtconsist c rhydrogen, eallsyl, a aryl, halogen and galkoxy rradica-ls,

Basis fa: member ,0155? the v-;group viwhichizoonsists of "hydro e al yl, car-"r1, lalkoxy, rand a moxy radicals,

R3 is a member :of the group WhiQhrQQHS'iStS-{Of hydro gen, alkyl and aryl radicals; and .a'lkylene cradieals; ingwhich. *casetfiislanditRaiandii carbon atoms linkedabyuthezdoubla bondatogether form a cyclo olefinic ring,

withr n-aque r l iian p ta sommu i selecte it the group wh th ,eqn i i j watcholubl u 'fiie {and h u fite i Whithih ceme t-i s lected from the group consisting .o'f metals ammonium, and =;N -substituted ammonium ions,

said solution having a pH of at least 5.4, and adding sulfur dioxide and'vthe i equired base at a ratio to maintain the reaction mixture ata pHof from 6 to 'land at a rate equivalentto theadded ,olefin.

8. A method of preparing fl-nitrosulfonic-compounds which comprises continuously :reacting a nitroolefin having the following structuraliormul with an aqueous solution of a compound selected from the group which consists of water soluble sulfites and bisulfites in which the cation is selected from the group consisting of metals, ammonium, and. N-substituted ammonium ions, said solution having a pH of at least 5.4, adding sulfur dioxide and the required base at a rate to maintain the reaction mixture at a pH of from 6 to 7 and at a rate equivalent to the added olefin, continuously removing a portion of the reaction mix- M tune, separating :the crystalline productv theretmm and returning the filtrate in a -.continucus mam nor to thereaction vmixture.

9. The method of preparing ,B-nitro sulfoniocompounds which comprises :reacting a nitro olefin havingthe fOIIOWiHgQStI UCtHI'QIL iformulat:

..R1I"R2 Nor=+ R3 wherein R1 is a member of the group which consists of ghrdrg en, iwa y a y ahaloee tend alls x :--1adi s,

R2 is a member of the group which consists .,of it m n a k er ,a Q y ;l:ari awr l xr -rsad ea R3 is a member of the group which consists of hs drogen allgyl and arylradicals ,andalkylene radicals in which -.case,R1 and 'io and the-oar- ;bomatomsj linked the double ibond together i smra cycl e e inicrin with an aqueous solutionof atisul-fiteselectiad irom the classlwhichconsists ei-metal :bisulfiif gs, ;b.; s r fite an ubst te ammonium-lbisuliites -said(solution having a pl-l at leastriiA.

;];0. method ;;of ,goreparing :{3-nitro .sultonic compounds wh c com e re ting x 5 1 3 olefin hating :the following--structuraleiormula:

N.o2 o=:

l tz wherein R1 is a member of the group which consists of hydrogen, alkyl, aryl, halogen and alkOJ (Y radicals, R2 is-amember"orrthe roupwhi hwe sists lof- :rhudroaen a ky :a yl, "a kosy 1 n a ry- 0x5 radicals, a Rs isoa memlc-ier-1,0f the groupwhich consists of rehydrogen-zalkylegand aryl=radica1s an alli ie radicals in which case R1 and R3 andi'themarsbonsatomsfiinked;gbythe fdouble -bondntogether {i0 rmaaicyclo. zolefinie ring, with an aqueous solution 'of ;a bisu1fite selected from the class which consists pf ymetal bisulfites, ammonium bisulfites and N substituted ammonium abisulfites, said :solution .zhaving a 5.111 Grimm-1'6 toi'l.

;-;11. A smethod -01 preparing :,-c,-nitro sulfQn-ic compounds whichcompriseslreacting; mole fin having :the iollowing estructural ;:;Eo1=n 1 i 1l a:

where with an aqueous solution of a bisufite selected from the class which consists of metal bisulfites, ammonium bisulfites and N-substituted ammonium bisulfites, said solution being such as to th erouplwbieh miSs; rf aryl, halogen and allgogy thagroup which consists of garyl, alkoxy, and aryloxy wherein R1 is a member of the group which consists of hydrogen, alkyl, aryl, halogen and alkoxy radicals,

R2 is a member of the group which consists of hydrogen, alkyl, aryl, alkoxy, and aryloxy radicals,

Rais a member of the group which consists of hydrogen, alkyl and aryl radicals and alkylene radicals in which case R1 and R3 and the carbon atoms linked by the double bond together form a cyclo olefinic ring,

with an aqueous solution of a bisulfite selected from the class which consists of metal bisulfites, ammonium bisulfites and N-substituted ammonium bisulfites, said solution having a pH of from 6 to 7, and maintaining the pH of the reaction mixture at a pH of from 6 to '7.

13. A method of preparing p-nitro sulfonic compounds which comprises continuously reacting a nitro olefin having the following structural formula:

3 wherein R1 is a member of the group which consists of hydrogen, alkyl, aryl, halogen and alkoxy radicals,

R2 is a member of the group which consists of hydrogen, alkyl, aryl, alkoxy, and aryloxy radicals,

R3 is a member of the group which consists of hydrogen, alkyl and aryl radicals and alkylene radicals in which case R1 and R3 and the carbon atoms linked by the double bond together form a cyclo olefinic ring,

with an aqueous solution of a bisulfite selected from the class which consists of metal bisulfites, ammonium bisulfites and N-substituted ammonium bisulfites, said solution having a pH of from 6 to 7, and adding sulfur dioxide and the required base at a ratio. to maintain a pH of from 6 to 7 and at a rate equivalent to the added olefin.

14. A method of preparing S-nitro sulfonic compounds which comprises continuously reacting a nitro olefin having the following structural formula:

wherein R1 is a member of the group which consists of hydrogen, alkyl, aryl, halogen and alkoxy radicals,

R2 is a member of the group which consists of hydrogen, alkyl, aryl, alkoxy, and aryloxy radicals,

R3 is a member of the group which consists of hydrogen, alkyl and aryl radicals and alkylene radicals in which case R1 and R3 and the carbon atoms linked by the double bond together form a cyclo olefinic ring,

with an aqueous solution of a bisulfite selected from the class which consists of metal bisulfites, ammonium bisulfites and N-substituted ammonium bisulfites, said solution having a pH of from 6 to 7, adding sulfur dioxide and the required base at a ratio .to maintain a pH of from 6 to 7 and at a rate equivalent to the added olefin, continuously removing a portion of the reaction mixture, separating the crystalline product therefrom, and returning the filtrate in a continuous manner to the reaction mixture.

15. A process for the preparation of ammonium-2-nitroethane-l-sulfonate which comprises reacting nitroethylene with an aqueous solution of ammonium bisulfite, the pH of which is from 6 to '7.

16. A process for the preparation of ammonium-Z-nitropropane-l-sulfonate which comprises reacting z-nitropropene with an aqueous solution of ammonium bisulfite, the pH of which is from 6 to '7.

1'7. A process for the preparation of ammonium-2-nitrobutane-l-sulfonate which comprises reacting 2-nitro-1-butene with an aqueous solution of ammonium bisulfite, the pH of which is from 6 to '7.

MARVIN H. GOLD.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 405,938 Andresen June 25, 1899 1,999,432 Ulrich Apr. 30, 1935 2,103,879 Ufer Dec. 28, 1938 2,170,380 Holsten Aug. 22, 1939 2,181,890 Harris Dec. 5, 1939 2,363,819 Von Glan Nov. 28, 1944 2,465,803 Heath et al Mar. 29, 1949 FOREIGN PATENTS Number Country Date 805,092 France Nov. 10, 1936 571,157 Great Britain 1945 OTHER REFERENCES Kharasch et al.: J. Org. Chem, vol. 3 (1938). Mayo: Chemical Reviews, vol. 27, pp. 394 to 399 (1940). 

1. A CHEMICAL COMPOUND HAVING THE FOLLOWING STRUCTURAL FORMULA:
 5. A METHOD OF PREPARING B-NITRO SULFONIC COMPOUNDS WHICH COMPRISES REACTING A NITRO OLEFIN HAVING THE FOLLOWING STRUCTURAL FORMULA: 